Arc element for a ventilation system

ABSTRACT

An arc element for a ventilation system has at least one oval opening and a flow cross-section with a minimum radius of curvature, which has at least the size of one tenth of the smallest diameter of this flow cross-section.

The present patent application claims the priority of the German patent application DE 10 2016 220 527.7, the content of which is hereby included by reference.

The invention relates to an arc element for a ventilation system. The invention further relates to a method for producing such an arc element. In addition, the invention relates to an assembly device for an arc element and an assembly set comprising an arc element and an assembly device. Finally, the invention relates to a ventilation system with a corresponding arc element.

With a ventilation system, the layout of pipe or duct elements often has to be adapted to given constructional circumstances. In this context, it may be necessary to deflect the air flow. Arc elements, also designated as pipe bends, can serve for this purpose. In general, arc elements of that kind lead to a flow resistance which may be quantified, for example, via a pressure loss. This has adverse effects on the efficiency of the ventilation system.

It is an object of the present invention to improve an arc element for a ventilation system.

This object is achieved by an arc element according to claim 1.

The essence of the invention is to configure the outer wall limiting an inner space of an arc element, which is configured ovally at least in the area of one of its ends, in a way that the flow cross-section of the inner space has a minimal radius of curvature being at least 1/10 of the minimal diameter of this flow cross-section.

The minimal radius of curvature of the flow cross-section of the inner space is in particular at least ⅕, in particular at least ⅓ of the smallest diameter of the flow cross-section.

The flow cross-section of the inner space, in particular, at any point has a corresponding minimal radius of curvature.

It has been found that by avoiding narrow radii of curvature in the flow cross-section, the flow resistance of the arc element and therewith the pressure loss resulting thereof may be reduced. In particular, it has been found that in this context it is advantageous to configure a so-called flat duct circularly as well. Especially the side walls of the flat duct may be configured by circular arc-like portions, in particular by semi-circular arches.

With reference to the flow cross-section, the minimal radius of curvature of same, in particular, at least has the size of one tenth of the root of the flow cross-section, in particular at least has the size of one fifth of the root of the flow cross-section, in particular at least has the size of one third of the root of the flow cross-section, in particular at least has the size of one half of the root of the flow cross-section.

In absolute terms, the radius of curvature is in particular at least 2.5 cm, in particular 3 cm, in particular 4 cm. This applies, in particular, for an arc element with a flow cross-section at the end of 100 cm², in particular at least 125 cm², in particular at least 150 cm², in particular at least 175 cm², in particular at least 200 cm². The indicated values of the radius of curvature in particular refer to an arc element with a flow cross-section at the end of a maximum of 250 cm².

According to one aspect of the invention, the arc element has openings on both ends with the same flow cross-section in terms of amount. Alternatively, the arc element on its one end may have another amount of flow cross-section than on the other end. The flow cross-sections may differ in particular by more than 10%, in particular by more than 20%. Usually, they differ by a maximum factor of 2.

According to one aspect of the invention, the arc element has an oval flow cross-section. It has an oval flow cross-section, in particular throughout its entire length. The oval may be configured in particular basically by two straight line sections and two semi-circles. Alternatively, the arc element may have an elliptic flow cross-section.

According to one further aspect of the invention, the arc element is a pipe bend or a duct bend. The arc element in particular serves for changing the direction of a pipe or duct system. By this means, a redirection of the medium to be conducted can be achieved. The redirection may be carried out in horizontal or vertical direction. In principle, it can be carried out in any direction.

According to one further aspect of the invention, the two openings at the ends of the arc element enclose an angle of at least 15°, in particular at least 30°, in particular at least 45°, in particular at least 60°, in particular 90°. The arc element in particular serves for redirecting the air flow by the corresponding angle.

According to one further aspect of the invention, the outer wall of the arc element is configured as one piece. By this means, an additional bonding connection may be avoided. This leads to cost-saving in the production of the arc element. Furthermore, the production becomes less prone to errors. Finally, handling the arc element upon production is facilitated by this means. Bonding single parts of the outer wall is not necessary. In particular, no additional material for finishing the outer wall is needed.

The arc element may, in particular, be configured as one piece as a whole. It may in particular be made of plastic material. Preferably, it may be made by means of an injection molding process. This facilitates the production, as well.

According to one further aspect of the invention, the arc element is made of a shape-retaining material. Alternatively, the arc element may, at least section-wise, be configured flexibly. It may, in particular, comprise a flexible central area. By this means, it is possible to adjust the angle enclosed between the two openings at the ends. For this purpose, the outer wall may comprise an area which is configured elastically.

According to one further aspect of the invention, all surfaces of the arc element coming into contact with the medium to be conducted have a high surface quality. For the average surface roughness Rz, in particular Rz<5 μm, in particular Rz<3 μm applies. Such a low average surface roughness Rz may be achieved by the production method of the arc element and/or by a surface treatment, in particular a surface refinement thereof.

According to one further aspect of the invention, the arc element has at least one flow guide element arranged in the inner space, which is configured as one piece with the outer wall. Preferably, the arc element as a whole is configured as one piece. The arc element may in particular have two, three, four, five or more corresponding flow guide elements.

Via corresponding flow guide elements, the flow resistance of the arc element may be reduced. A one-piece configuration of the arc element leads to the advantages as already mentioned above.

According to one further aspect of the invention, the at least one flow guide element is configured double curved. In particular in flow direction, it has a curvature, in particular corresponding to the curvature of the arc element. Furthermore, it has a curvature in a plane of a flow cross-section.

The flow guide element may in particular have a form which may be described by a section of a torus surface. It has in particular two constant radii of curvature. Alternatively, it is possible to configure the at least one flow guide element with a radius of curvature varying in at least one direction, i.e. with a non-constant radius of curvature. The radius of curvature of the at least one flow guide element may vary, i.e. be non-constant, in particular in flow direction and/or vertically to the flow direction.

The smaller one of the radii of curvature of the at least one flow guide element has at least the same size as the minimum radius of curvature of the flow cross-section of the inner space.

The radii of curvature of the flow guide elements are in particular smaller than 10 m, in particular smaller than 5 m, in particular smaller than 3 m, in particular smaller than 2 m, in particular smaller than 1 m.

According to one further aspect of the invention, the arc element has a flow cross-section varying in flow direction. The arc element may in particular have a flow cross-section varying in flow direction in terms of amount. The arc element may have a flow cross-section that is decreasing section-wise and then increasing again in flow direction, in particular starting from the first opening. The arc element may, in particular in flow direction, first configure a confusor and a diffusor adjacent thereto. It may also exclusively configure a confusor or a diffusor.

According to one further aspect of the invention, one of the openings at the ends of the arc element has a circular shape. The arc element in this case configures a transition piece from an oval flow cross-section to a circular flow cross-section. It may in particular serve as a transition piece from a flat duct to a round duct.

The cross-section of the circular opening may here be just as large as the cross-section of the oval opening of the arc element. The cross-section of the circular opening may also be smaller than the cross-section of the oval opening. It may be smaller in particular by at least 5%, in particular by at least 10% than the flow cross-section of the oval opening. Preferably, it is smaller by at most 30%, in particular smaller by at most 20% than the cross-section of the oval opening. In principle, the cross-section of the circular opening may also be larger, in particular by at least 5%, in particular by at least 10%, in particular by at most 20%, in particular by at most 30%, than the cross-section of the oval opening.

The outer wall may in this case be configured by freeform surfaces. The inner space of the arc element is in particular free from undercuts.

The outer wall of the arc element may in this case be configured in particular in two parts. The two parts may be connected with one another via a tongue and groove connection. This leads to a particularly simple and reliable positioning of the two molded parts.

The two parts may in particular be held together by means of a latch.

According to one alternative, a bead for glue to stick the two parts of the outer wall of the arc element together is provided along the parting line. Hereby, a liquid-tight, in particular a gas-tight connection of the two parts of the arc element is facilitated.

With this alternative, it is possible to configure at least one flow guide element separately from the outer wall and to install it in the inner space. The separate flow guide element may in particular be loosely slid into the inner space of the arc element. It may, in particular in the area of the oval opening of the arc element and/or in the area of the circular opening of the arc element, be fixed in the arc element by means of guiding and/or fixing means. Guiding rails and/or latching elements may serve as guiding and/or fixing means. It may also at least partially be inserted in the outer wall of the arc element with positive locking. With any of the different alternatives of the arc element, the flow guide elements may be arranged in the inner space in a way that they split the flow cross-section into equal parts in terms of amount. It may also be provided to arrange the flow guide elements in a way that the flow cross-section is divided in sections of different sizes. For example, the section on the inside of the curvature of the arc element may be smaller than the one on the outer side of the curvature of the arc element. The position and arrangement of the flow guide elements in the inner space of the arc element may in particular be chosen in a way that upon throughflow of the arc element by a predefined air flow, a particularly even velocity profile of the air flow results on the outlet side. A corresponding arrangement of the flow guide elements may be determined, in particular optimized by means of a simulation process.

According to one further aspect of the invention, the arc element has a ratio of flow cross-section, in particular on the side of the outlet of the flow cross-section, and hydraulic diameter of at most 15 cm, in particular at most 12 cm, in particular at most 10 cm. It is one further object of the invention to improve a method for producing an arc element according to the above-mentioned description.

This object is achieved by a method in which the outer wall of the arc element and the at least one flow guide element are produced in one single process step.

As a result of this, no additional bonding connections are needed anymore. This leads to cost savings due to the abolition of an additional working step. Furthermore, this leads to a reduction of the susceptibility to errors and facilitates the handling of the arc element upon production.

The arc element may in particular be made by means of an injection molding process.

One further objective of the invention is to provide for an assembly device for an arc element.

This objective is achieved by an assembly device with a base plate, at least two guiding elements arranged on the base plate and at least one fixing element for fixing the arc element relative to the base plate, wherein the at least one fixing element may be connected force-fit or form-fit with at least two of the guiding elements.

The assembly device allows for particularly simple mounting of the arc element.

According to one aspect of the invention, a number of oblong holes is arranged in the base plate. The oblong holes are aligned in particular angularly to one another, in particular vertically to one another. The oblong holes may be arranged on the inside and/or on the outside of the guiding elements, respectively. In particular, it is possible to arrange the oblong holes in pairs, respectively, in the area of the guiding elements, wherein one of the oblong holes, respectively, is arranged inside and one of the oblong holes is arranged outside one of the guiding elements. While doing so, the oblong holes in the area of one guiding element may be aligned vertically to those in the area of the other guiding element.

The base plate may be braced. It may in particular be profiled.

The guiding elements may have a length of at least 10 cm, in particular at least 12 cm, in particular at least 15 cm, in particular at least 18 cm. The length of the guiding elements is in particular at most 35 cm, in particular at most 30 cm, in particular at most 25 cm. The length of the guiding elements predefines a maximum adjustment track for aligning the arc elements.

The guiding elements may have parting lines for variable shortening. They may have latching means which may interact with matching latching means of the fixing element.

The guiding elements may in particular be provided with a sawtooth structure on their surface.

According to one further aspect of the invention, the guiding elements and the fixing element have matching latching means, respectively, by means of which they may be interlocked. The fixing element may in particular be arranged variably adjustable on the guiding elements.

The fixing element may in particular be detachably connected with the guiding elements.

The fixing element may in particular be configured as a strap, which may be slid onto the guiding elements and be locked therewith.

The strap may be adjusted on its inside to the form of the outer wall of the arc element. It may have in particular clamping elements matching the structures of the outer wall of the arc element. The arc element may thus be clamped, in particular fixed, in particular fixed between the two guiding elements, to the base plate by means of the fixing element.

With the help of a fixing element, the arc element may be arranged in particular in a variable distance to the base plate between the guiding elements.

One further object of the invention is to provide an assembly set with an arc element and a matching assembly device.

This object is achieved by an assembly set with an arc element and an assembly device according to the foregoing description.

The advantages follow from those of the arc elements or those of the assembly device.

According to one aspect of the invention, the arc element has spatial structures on its outside, for example in the form of a bushing, which form-fit to areas of the guiding elements and/or the fixing elements provided for this purpose upon arranging the arc element in the assembly device. As a result of this, a safe arrangement of the arc element in the assembly device is ensured.

According to one further aspect of the invention, the assembly set comprises one or more sealing elements by means of which a tight, in particular a liquid-tight, preferably a gas-tight connection between a flat or a round duct and the arc element may be established.

Via such a sealing element, mounting of the arc element, in particular the connection thereof with an adjacent duct or pipe element is facilitated significantly.

One further object of the invention is to improve a ventilation system, in particular an extractor fan system for a kitchen stove.

This object is achieved by a ventilation system with at least one arc element according to the foregoing description. The ventilation system is in particular an extractor fan system with a device for extracting cooking fumes from a hob level. The device for extracting cooking fumes is connected, in particular via a ventilation duct, with an arc element according to the foregoing description with an air outlet.

The advantages follow from those of the arc element. In particular, the reduced flow resistance of the arc element leads to more efficient extraction of cooking fumes with a given extractor fan device.

Further advantages and details of the invention follow from the description of exemplary embodiments on the basis of the figures, in which:

FIG. 1 schematically shows an extractor fan system for a kitchen stove,

FIG. 2 shows a view of an assembly set with an arc element and a matching assembly device,

FIG. 3 shows an isolated view of the arc element according to FIG. 2,

FIG. 4 shows an isolated view of the assembly device according to FIG. 2,

FIG. 5 and FIG. 6 show views of the components of the assembly device according to FIG. 4,

FIG. 7 shows a view of an arc element according to an alternative,

FIG. 8 shows a view of an arc element according to FIG. 7 from a different perspective,

FIG. 9 shows a sectional representation along the line IX-IX of the arc element according to FIG. 8,

FIG. 10 shows a further view of the arc element according to FIG. 2 with a duct element connected therewith on one side,

FIG. 11 shows a section along the line XI-XI through the arc element with the connected duct element according to FIGS. 10, and

FIG. 12 shows an exemplary representation of a sealing element.

In the following, first the general components of an extractor fan system 1 for a kitchen stove are described. The extractor fan system 1 in general configures a ventilation system. It comprises a fan 2 for producing an air flow. The fan 2 is connected with an outlet unit 4, in particular with an air outlet opening, via a ventilation duct 3. The outlet unit 4 may in particular be a wall sleeve or an air circulation unit.

The extractor fan system 1 further comprises an extractor fan device 5. The extractor fan device 5 may in particular be a so-called downdraft system, i.e. an extractor fan drawing fume downwards from a hob level 6. It may in particular be a hob extractor system.

The extractor fan device 5 comprises a fume inlet device 7. The fume inlet device 7 may be arranged adjacent to a hob 8. In particular, it is arranged between two hobs 8. It may also be integrated in a hob system 9 with at least one, in particular more hobs 8. The hobs 8 and the fume inlet device 7 may in particular be combined to one assembly unit. As a result of this, inter alia the installation of the hob system 9 is facilitated.

The extractor fan device 5 is connected flow-mechanically with the fan 2 via a connection duct 10. The connection duct 10 may comprise one or more pipes, ducts or tubes. It may in particular comprise an arc element 11, which will be described in more detail in the following.

The connection duct 10 is arranged in particular on the rear side of kitchen base element 12 with drawers 13 or compartments.

The fan 2 is arranged in particular in the plinth area 14 of the kitchen base elements 12.

An arc element 11 may also be provided in the ventilation duct 3 which connects the fan 2 and the outlet unit 4 flow-mechanically.

The representation and the description of the ventilation system in the form of the extractor fan system 1 are to be understood as an example only. Alternative configurations thereof, in particular alternative layouts of the connection duct 10 and/or the ventilation duct 3 are not only possible, they are to be expected. In general, in particular the layout of the connection duct 10 and/or of the ventilation duct 3 may be adapted very flexibly to the constructional circumstances.

In the following, details of the arc element 11 as well as of a matching assembly device 15 are described with reference to FIGS. 2 to 6.

The arc element 11 has an outer wall 16. The outer wall 16 limits an inner space 17 of the arc element 11.

The outer wall 16 is configured as one piece. It is made of plastic material, in particular of a shape-retaining plastic material. It is in particular made of a heat-resistant and fire-resistant material. It is heat-resistant in particular at least up to a temperature of 60° C., in particular at least up to a temperature of 90° C., in particular up to a temperature of at least 120° C.

The outer wall 16, in particular, is made of a normally inflammable or hardly inflammable material (material class DIN 4102-1 B2 or B1).

The arc element 11 has one opening 18, 19, respectively at its ends. The openings 18, 19, respectively, are surrounded by a border, in particular in the form of a bushing 20, 21.

On the outside of the arc element 11 in the area of the bushings 20, 21, one contact surface 29, respectively, is arranged. The contact surface 29 has a linear outer rim 30. The contact surfaces 29 facilitate an arrangement of the arc element 11 in which the straight sections 24, 25 of the inlet are aligned in parallel to the vertical direction.

The first opening 18 is oriented vertically to a first direction 22. The second opening 19 is oriented vertically to a second direction 23. The directions 22, 23 enclose an angle of 90° with each other. In general, the directions 22, 23 enclose an angle of at least 15°, in particular of at least 30°, in particular of at least 45°, in particular of at least 60° with each other.

The first opening 18 is configured ovally. It has a cross-section which is limited by two straight sections 24, 25 and two semicircular sections 26, 27.

According to an alternative not shown in the figures, the first opening 18 has an elliptic cross-section.

The first opening 18 has a largest diameter d_(max) and a smallest diameter d_(min). The ratio d_(max):d_(min) is at least 1.5:1, in particular at least 2:1, in particular at least 2.5:1. The arc element 11 is therefore also designated as flat duct arc.

The first opening 18 will also be named as inlet in the following. Accordingly, the second opening 19 will also be named as outlet in the following. This is not to be understood as a limitation. The second opening 19 may in particular serve as an inlet and the first opening 18 may also serve as an outlet.

The first opening 18 has a flow cross-section within the range of 175 cm² to 200 cm². In general, the flow cross-section of the inlet of the arc element 11 is at least 100 cm², in particular at least 125 cm², in particular at least 150 cm². It is in particular at most 500 cm², in particular at most 300 cm².

The same indications also apply for the outlet of the arc element 11. Inlet and outlet may in particular be configured identically. They may in particular have the same flow cross-section at least in terms of amount, in particular have the same flow cross-section with regard to their form. It is also possible to configure the arc element 11 with an inlet and an outlet having different flow cross-sections. Such an alternative will be described in more detail in the following.

According to the alternative of the arc element 11 shown in FIG. 3, the flow cross-section of the inner space 17 has a minimum radius of curvature r_(min) in the area of the inlet, which precisely corresponds to half of the minimum diameter d_(min) of the inlet, r=d_(min)/2. In general, the flow cross-section of the inner space 17, in particular in the area of the openings 18, 19, in particular at any random point, has a minimum radius of curvature rmin which has at least the size of one tenth, in particular at least the size of one fifth, in particular at least the size of one fourth, in particular at least the size of one third of the smallest diameter d_(min) of this flow cross-section, r_(min)≥d_(min)/10, in particular r_(min)≥d_(min)/5, in particular r_(min)≥d_(min)/4, in particular r_(min)≥d_(min)/3.

In absolute figures, the minimum radius of curvature rmin of the flow cross-section of the inner space 17 in the area of the openings 18, 19, in particular at any random point of the arc element 11, is at least 2 cm, in particular at least 3 cm, in particular at least 4 cm.

In the inner space 17 of the arc element 11, three flow guide elements 28 ₁, 28 ₂, 28 ₃ are arranged. The flow guide elements 28 ₁, 28 ₂, 28 ₃ subdivide the inner space 17 into four separate flow channels.

In general, in the inner space 17 of the arc element 11, at least one flow guide element 28 is arranged. Preferably, the number of flow guide elements 28 _(i) is two, three or more.

In the alternative of the arc element 11 shown in FIG. 3, the flow guide elements are configured in one piece with the outer wall 16. In this alternative, the entire arc element 11 is in particular configured in one piece.

Alternatively, the flow guide elements 28 i may also be configured separately from the outer wall 16 and be arranged in the inner space 17 of the arc element 11. They are in particular stationarily defined relative to the outer wall 16.

The flow guide elements 28 i are configured double curved. They have in particular a first curvature direction corresponding to the curvature of the arc element 11. Furthermore, they have a curvature in the plane of the flow cross-section A.

The flow guide elements 28 i, respectively, may have a shape corresponding to a section of the surface of a torus.

The flow guide elements 28 _(i) have an increasing radius of curvature when their distance to the inner curve side of the arc element 11 increases. The radii of curvature R (28 _(i)) of the flow guide elements 28 i have been chosen in particular as follows: 100 mm≤R (28 ₁)≤150 mm, in particular R (28 ₁)=ca. 120 mm; 140 mm≤R(28 ₂)≤190 mm, in particular R (28 ₂)=ca. 165 mm; 200 mm≤R(28 ₃)≤250 mm, in particular R (28 ₃)=ca. 224 mm.

In particular, it is possible to configure the flow guide elements 28 _(i) in a way that all flow guide elements 28 _(i) have the same center of curvature M.

In an especially advantageous embodiment not shown in the figures, this configuration may also be modified to the effect that the flow guide elements 28 _(i), seen in flow direction, have a changing radius of curvature. By this means, the flow properties in the arc element 11 may be further improved, in particular optimized. In particular, it is possible to optimize the shape of the flow guide elements 28 _(i) in a way that the velocity profile of a flow in the area of the outlet of the arc element 11 is essentially homogeneous, in particular at most deviates by a predefined maximum value from the average value. Basically, other flow profiles may also be predefined.

Furthermore, the flow guide elements 28 _(i), with reference to a flow cross-section plane, may also have a radius of curvature changing throughout the corresponding extension of the flow guide element 28 _(i).

In the alternatives shown in the figures, the flow guide elements 28 _(i) have one curvature, respectively, pointing outward from the center of curvature M of the arc element 11. They have in particular a curvature that is convex, seen from the center of curvature M, in particular a curvature that is double convex.

According to an alternative not shown in the figures, the flow guide elements 28 _(i) have a concave curvature in a vertical plane extending in radial direction, in particular in the area of the first opening 18 and/or the second opening 19. They may also be S-shaped, that is configured convex-concave. The flow guide elements 28 _(i) may be configured in view of their curvature properties to each other. They may also be configured differently. In particular, it is possible to configure one of the flow guide elements 28 _(i) convexly curved, and the other one concavely curved. This may in particular be advantageous if different flow channels are to serve for different purposes.

In the direction of the width of the flow cross-section A of the arc element 11, the flow guide elements 28 _(i) may be arranged in the inner space 17 in particular in a way that the flow channels defined by the flow guide elements 28 _(i), respectively, have the same flow cross-section A in terms of amount.

According to one especially advantageous alternative, the flow guide elements 28 _(i) are arranged in particular in a way that the individual flow channels, respectively, have an essentially identical hydraulic diameter.

Alternatively, it is also possible to arrange the flow guide elements 28 _(i) in a way that the flow channels have a flow cross-section A increasing towards the outside of the curve.

According to an alternative not shown in the figures, the arc element 11 has a flow cross-section A that is varying in flow direction. It has been shown that by this means, as well, a pressure loss upon throughflow of the arc element 11 may be further reduced.

It is intended to produce the outer wall 16 of the arc element 11 and the flow guide elements 28 _(i) in one single common process step. The arc element 11 may in particular be produced by means of an injection molding process. This allows for a particularly simple, reliable production of the arc element 11.

In the following, the assembly device 15 for mounting the arc element 11 will be described in more detail. The assembly device 15 configures an assembly set 40 together with the arc element 11, respectively 11 a. The assembly device 15 comprises a base plate 31. On the base plate, two rod-like guiding elements 32 are arranged. The guiding elements 32 are also named as guiding rods.

The base plate 31 with the guiding elements 32 arranged thereon is also named as suspension 39.

On the guiding rods, latching means in the form of a toothing 33 are configured.

The latching means on the guiding rods interact with matching latching means of a fixing element in the form of a fixing strap 34. The latching means of the fixing strap 34 are configured as leaf spring elements 35. They are integrated in a guiding structure 36 for guiding the fixing element on the guiding elements 32. The guiding structure 36 is essentially configured by two flat elements sticking vertically outward the fixing strap 34. Alternatively, it may be provided to configure the guiding structure 36 as a guiding duct. The guiding duct has in particular an inner, free cross-section which is adapted to the outer cross-section of the guiding rod.

On the inside of the fixing element, on both sides, respectively, a clamping nose 37 is provided. The clamping nose 37 serves for clamping the bushings 20, 21 and therewith for fixing the arc element 11 between the two guiding elements 32.

An additional fixing of the arc element 11 in the assembly device 15 may be achieved by the contact surfaces 29. The contact surfaces 29 may interact with groove-like recesses, intended for this purpose, of the guiding elements 32. They may also lie firmly on one side of the guiding elements 32. With the help of the contact surfaces 29, which interact with the guiding elements 32, it is in particular possible to secure the arc element 11 against displacement along the first direction 22 on the assembly device 15.

The fixing strap 34 is adjustable on the guiding elements 32. By this means, in particular the distance of the fixing strap 34 to the base plate 31 is adjustable.

The guiding elements 32 can be cut to length. It is in particular possible to cut off the part that is not required starting from the free end of the guiding elements 32.

The fixing strap can in particular be slid onto the guiding elements 32. It is secured by the leaf spring elements 35, which interact with the toothing 33 on the guiding elements 32, against displacement in the direction of the of the guiding elements 32 away from the base plate 31.

With the help of the assembly device 15, the arc element 11 may be set relative to the assembly device 15 and therewith relative to the structure of a building or furniture the assembly device 15 is fixed on. With the help of the fixing strap 34, on the one hand a reliable fixation of the arc element 11 in the assembly device 15 is possible, on the other hand the fixing strap 34 also allows for being removed again from the guiding elements 32 and thus to withdraw the arc element 11 from the assembly device 15.

The assembly device 15 is flexibly mountable horizontally, in particular to a floor or a ceiling, or vertically, in particular to a wall.

For fixing the base plate 31 to a floor, a wall or a ceiling or another structure, oblong holes 38 are provided in the base plate 31. In particular two oblong holes 38, respectively, are provided in the area of one of the guiding elements 32. The two oblong holes 38, in particular, are arranged on opposite sides of one of the guiding elements 32, respectively. The oblong holes 38 in the area of one guiding element 32 are in particular arranged in parallel to the longitudinal direction of the base plate 31. The other two oblong holes 38, preferably, are arranged vertically to the longitudinal direction of the base plate 31. This allows for an especially simple, precise fixing of the base plate 31 to a ground.

In order to increase the stiffness, the base plate 31 is configured profiled.

The base plate 31 may be provided with parting lines 41. The parting lines 41 are in particular arranged on the outside of the guiding elements 32, respectively. They allow for easy shortening of the base plate 31. By this means, in particular a mounting of the assembly device 15 directly adjacent to a side wall is provided for. With such an arrangement of the assembly device 15, the guiding elements 32 may have a distance of less than 1 cm, in particular of less than 0.5 cm to a side wall.

When arranging the fixing strap 34 on the guiding elements 32, a circumferentially entirely closed accommodation area for accommodating the arc element 11 is configured. The accommodation area is configured on the one hand by the fixing strap 34, on the other hand by the base plate 31 and, as the case may be, by one section of the guiding element 32 adjacent to the base plate 31, respectively.

The distance of the guiding elements 32 is adapted to the dimensions of the arc element 11, in particular to the largest diameter of the inlet of the arc element 11. This should be understood as meaning that the distance of the two guiding elements 32 on the base plate 31 precisely corresponds to the largest outer diameter of the arc element 11 in the area of the inlet and/or the outlet, in particular in the area adjacent to the bushings 20, 21.

In the following, one further alternative of an arc element 11 a will be described with reference to FIGS. 7 to 9. Identical elements and components obtain the same reference numbers as in the description of the arc element 11, which is herewith referred to.

The arc element 11 a configures a transition piece from a flat duct to a round duct. As it is shown in FIG. 7 by way of example, the second opening 19 of the arc element 11 a is configured circularly. Regarding the first opening 18, reference is made to the description of the arc element 11.

The arc element 11 a may also have an outer wall 16 configured in one piece.

Alternatively, the outer wall 16 of the arc element 11 a may also be configured in two pieces. It may in particular be configured in two parts 42, 43, which are configured by a freeform surface, respectively. The two parts 42, 43 of the outer wall 16 of the arc element 11 a are in particular free from undercuts. The two parts 42, 43 of the outer wall 16 of the arc element 11 a may for example be connected with each other via a tongue and groove connection. This allows for a particularly simple and reliable positioning of the two molded parts of the arc element 11 a relative to one another. The two parts 42, 43 of the outer wall 16 of the arc element 11 a may be fixed to one another by means of clamps 44. The may also be glued to one another. For this purpose, as well as for sealing the connection of the two parts 42, 43, a bead may be provided in the area of the connecting line.

The arc inside part 43 is connected with the bushing 21 that is preferably configured in one piece, in particular configured in one piece with same.

According to the alternative shown in FIGS. 7 to 9, one single flow guide element 28 is provided with the arc element 11 a. A different number of flow guide elements 28 _(i) is possible, as well, with the arc element 11 a.

The flow guide element 28 is in particular configured single-curved. In parallel to the axis of curvature, it has in particular an essentially linear routing.

In this alternative, it may be advantageous to configure the flow guide element 28 separately from the outer wall 16 of the arc element 11 a. The flow guide element 28 may then be inserted in the inner space 17 of the arc element 11 a and fixed therein.

In the area of the bushing 21, on the inside of the outer wall 16 of the arc element 11 a, pairs of fixing bars 45 are arranged, respectively. Between the two fixing bars 45 of one pair, an accommodating groove 46 for accommodating the flow guide element 28 is configured. The flow guide element 28 may in particular be glued into the accommodating groove 46.

A locking of the flow guide element 28 with matching latching means, in particular in the area of the bushing 21, is also possible.

In the area of the first opening 18, the flow guide element 28 is integrated, preferably form-fit, in the outer wall 16 of the arc element 11 a (see FIG. 9). It has in particular one side section 47, respectively, which continues the inner contour of the outer wall 16 essentially smoothly, in particular without edges. Towards its end, the side section may have a groove 48 for accommodating the first part 42 of the outer wall 16.

The second part 43 of the outer wall 16 is stepped several times in this area, in particular stepped twice. The flow guide element 28 thus is fixed between an edge 49 at the end of the first part 42 and a step 50 in the second part 43. Additionally, it may be fixed by a second step 51 in the second part 43.

The edge 49 at the end of the first part 42 interlocks in particular in the groove 48 in the side section 47 of the flow guide element 28.

Preferably, the flow guide element 28 is configured and arranged in a way that the ratio of the surface areas of the two separate sections 52, 53 defined by the flow guide element 28 in the area of the first opening 18 precisely corresponds to the ratio of the surface areas of the corresponding sections 54, 55 in the area of the second opening 19: A₅₂:A₅₃=A₅₄:A₅₅.

In the following, with reference to the FIGS. 10 to 12, the connection of the arc element 11 will be described according to the aforementioned description with a transition piece, in particular in the form of a flat duct element 56. Instead of the arc element 11, the flat duct element 56 may as well be connected with the arc element 11 a.

The flat duct element 56 is slid into the bushing 21 at the end of the arc element 11. It overlaps the bushing 21 essentially along its entire length in flow direction. The inside of the flat duct element 56 configures an essentially smooth, in particular edgeless continuation of the inside of the arc element 11.

In the area between the flat duct element 56 and the bushing 21, a sealing element 57 is arranged, as shown by way of example in FIG. 12. The sealing element 57 is pulled over the flat duct element 56. Together with the flat duct element 56, it will be inserted into the arc element 11, in particular into its bushing 21. It leads to a tight, in particular liquid-tight, preferably gas-tight connection between the flat duct element 56 and the arc element 11.

With the help of the sealing element 57, the assembly of the arc element 11, in particular the connection thereof with the adjacent flat duct element 56, is facilitated substantially. This leads to considerable time saving. Furthermore, the tightness of the connection between the flat duct element 56 and the arc element 11 may be ensured in a simple way with the help of the sealing element 57.

The sealing element 57 is made of flexible material. The sealing element 57 is preferably made of an elastic material. It may in particular be made of rubber. It entirely encloses a free end of the flat duct element 56 circumferentially. On one side, it has a rim 58 slightly projecting inwards. The rim 58 closely fits to a free rim at the end of the flat duct element 56 in the state of the sealing element 57 being pulled over the flat duct element 56.

In the state of flat duct element 56 being inserted into the arc element 11, the rim 58 comes to rest between the free rim of the flat duct element 56 and a contact shoulder 59 configured by the bushing 21.

The sealing element 57 has three circumferential sealing lips 60. It has in particular at least one sealing lip 60. It may as well have two or more than three sealing lips 60.

The sealing lips 60 may be configured with different heights. They lead to a tight, in particular a liquid-tight, preferably a gas-tight connection between the flat duct element 56 and the sealing element 57, and thus between the duct or pipe element and the arc element 11.

The sealing element 57 may be a component of the arc element 11 or the arc element 11 a or be a component of the flat or round duct element. It may, in particular as a separate element, configure a component of the assembly set 40. The sealing element 57 may lead to a tight connection of a flat or round duct element with the arc element 11, in particular in the ventilation system 1.

In the following, further advantageous details of the arc element 11 or 11 a and the assembly device 15 will be described again separately.

The radius of curvature of the flow guide elements 28 i in a flow cross-section plane lies in particular within a range of 50 mm to 500 mm.

The guiding elements 32 have a length within the range of 5 cm to 20 cm.

The toothing 33 may provide for an adjustment track within the range of 5 cm to 20 cm.

The base plate 31 has in particular a constructional height within the range of 5 mm to 15 mm, in particular within the range of 8 mm to 12 mm. Thus, at the same time, it serves as a spacer between the arc element 11 and a structure of a building or furniture the arc element 11 is arranged on.

Due to the assembly device 15, the assembly of the arc element 11 and therewith of the entire ventilation duct 3 and/or connection duct 10 is facilitated considerably. 

1. An arc element for a ventilation system comprising 1.1. an outer wall limiting an inner space of the arc element, 1.2. a first opening aligned vertically to a first direction, 1.3. a second opening aligned vertically to a second direction and 1.4. at least one flow guide element arranged in the inner space, 1.5. wherein the at least one flow guide element is configured double curved, whereby the at least one flow guide element has a curvature in flow direction and has a curvature in a plane of a flow cross-section (A) of the inner space.
 2. The arc element according to claim 1, wherein the at least one flow guide element is configured as one piece with the outer wall.
 3. The arc element according to claim 1, wherein the at least one flow guide element is configured separately from the outer wall and is at least partially inserted in the outer wall of the arc element with positive locking.
 4. The arc element according to claim 1, comprising an elliptic flow cross-section (A).
 5. The arc element according to claim 1, wherein all surfaces of the arc element coming into contact with the medium to be conducted have an average surface roughness (Rz) of less than 5 μm.
 6. The arc element according to claim 1, wherein the outer wall has an elastic area.
 7. The arc element according to claim 1, comprising a flow cross-section (A) varying in flow direction.
 8. The arc element according to claim 1, wherein one of the openings has a circular shape.
 9. The arc element according to claim 1, wherein it has a maximum ratio of flow cross-section (A) and hydraulic diameter of 15 cm.
 10. The arc element according to claim 1, wherein the outer wall of the arc element and the at least one flow guide element are produced in one single process step.
 11. (canceled)
 12. (canceled)
 13. (canceled)
 14. An assembly set comprising 14.1. an arc element according to claim 1 and 14.2. an assembly device comprising 14.2.1 a base plate, 14.2.2. at least two guiding elements arranged on the base plate and 14.2.3. at least one fixing element for fixing the arc element relative to the base plate, 14.2.4. wherein the fixing element may be connected with at least two of the guiding elements with one of the group comprising force-locking and positive locking.
 15. The assembly set according to claim 14, wherein the arc element has spatial structures on its outside, which are positively locked with corresponding areas of at least one of the group comprising the guiding elements and the fixing element upon arranging the arc element in the assembly device.
 16. The assembly set according to claim 14, wherein it comprises at least one sealing element for sealing the connection of a duct element with the arc element.
 17. A ventilation system with 17.1. a fan for producing an air flow, 17.2. wherein the fan is connected with an air outlet opening via a ventilation duct with at least one arc element according to claim
 1. 18. The arc element according to claim 1, wherein at least one of the openings is configured ovally with a ratio between largest diameter (d_(max)) and smallest diameter (d_(min)) of at least 1.5:1.
 19. The arc element according to claim 18, wherein the flow cross-section (A) of the inner space has a minimum radius of curvature (r_(min)), which has the size of at least one tenth of the smallest diameter (d_(min)) of this flow cross-section (A), r_(min)≥d_(min)/10. 